Perforation cleaner for oil wells



Dec. 10, 1940. s. v. SMITH PERFORATION CLEANER FOR OIL WELLS Filed Feb. 6; 1940 A /N VENTO/, 6A MUEL I/ JM/ TH Patented Dec. 10, 1940 UNITED ,STATES PATENT OFFICE" rERFoRATIoN CLEANER Fon on. WELLS samuel v. smith, Long Beach, caux. Application February s, 1940, serialNo. 317,553

1s claims.

My invention relates to means for servicing oil wells and more particularly is directed to a mechanical device for cleaning perforations in an oil well liner.

When an oil well is in production the perforations in the oil well liner through which fluids ow from the surrounding formations tend to become clogged with resultant reduction of oil now. The clogging may be caused by solids from 10.V` the well strata, by the formation of scale, or by corrosion arising from chemical action. In any event progressive clogging is inevitable under the best operating conditions and periodical cleanv ing of the perforations is necessary if the pro- 15 duction of. the well is to be maintained.

Mechanical'cleaning of liner perforations, as distinguished froml chemical and hydraulic procedures, provides positive action against the clogging material and may be completed in a thor- "gq ough manner in a relatively short operating period. Mechanical cleaning of liner perforations, however, involves serious diiculties because of the remoteness of the liner from the. operator, the multiplicity of the perforations that must 2"5 be reached mechanically, the relatively small -size of the perforations, the tenacity and solid character of the clogging material, the danger of the mechanical cleaning device becoming lodged in the liner, and the possibility of clean- 'a ing members binding or breaking oi in the `liner perforations.

The general object of my invention is to meet these various difliculties in the design of an efcientmechanical device for rapidly and thoroughly cleaning the multiple perforations in an oil well liner.

For the purpose of performing the cleaning operation in a rapid manner, I provide a plurality of cleaning members on 'a common car- 0 rier. One` object of my invention is to cause thev plurality of cleaning members to reach all of the perforations of a. liner.

tribute the cleaning members in radial disposition throughout the whole circumference of the 4j; liner.` A feature of my invention is the conception that the registration o! the cleaning members with the various perforations Vmay be further favored by progressively rotating the cleaner assembly and that such progressive rotation 5o may be derived from the twisting and untwisting of a cable through the medium of a differential swivel.

One object of my invention is to provide prying action to dislodge material from the perfora- 55 tions, the prying action being at least in part To this end I disdirected inward to force a substantial portion of the clogging material into the interior of the lining. .In the preferred form of my invention I propose to apply the prying action alternately from opposite directions against each perfora- 5 tion.

Another object of my invention is to provide a construction for a mechanicall perforation cleaner that is yielding in certain unimportant respects to reduce the danger of the device binding in the liner and to reduce the likelihood of cleaning membersbinding or breaking in the perforations. Morespecifically stated, it is my object to make the carrier for the cleaning members substantially smaller than the liner in cross section and to mount the cleaning members on the carrier in what may be termed a floating manner, the cleaning-members being extended from the carrier and adapted to yield both by retraction and by rotation. It is my further object to employ cleaning members adapted to yield by rotating from one disposition through horizontal to a reverse disposition when directed against and carried past any formidable obstruction on the inner -surface of the liner.

'Ihe above and other objects of the invention will be apparent from the following detailed description, taken' with the accompanying drawing.

In the drawing, which is 'to be taken as illustrative only:

Fig. 1 is a perspective view of a device comprising the preferred form of my invention;

Fig. 2 is an axial section .on a greatly enlarged scale of the upper end of the device, the section including the uppermost perforation-cleaning member;

Fig. 3 is a transverse section taken as indicated by the line 3-3 of Fig. 2;

Fig. 4 is a, fragmentary longitudinal section of the device in a perforated liner showing the dis- 0 lposition of a. perforation-cleaning member at the end of a downward movement of the carrier;

Figs. 5 to 8 are similar views in side elevation showing successive positions of the perforationcleaning member at successive points in the. subsequent upward movement of the carrier;

Figs. 9 and 10 are similar views showing the disposition of the perforation-cleaning member at successive points in the downward movement f of the carrier; and

Fig. 11 is a longitudinal section through an oil well. tubing or liner showing the manner in which a perforation-cleaning membermay be rotated through horizontal to a reverse position B5 if the member is forced against an obstruction on the inner surface of a tubing or liner.

The device shown in the drawing comprises a plurality of cleaning members 20 movably and 5 yieldably mounted on a frame or carrier 2|, the carrier being adapted for attachment to the lower end of a cable 22.. Preferably the cleaning members are in the form of blades and are both retractable and adapted for pivotal l0 movement. `It is also to be preferredgthat the -radial dimensions of the blades 20 with respect to the axis of the carrier 2| be distributed through 360. It is apparent that the indicated relationships and functions may be achieved in 16 various structural arrangements. The particular construction shown in the drawing has outstanding advantages that have made it a success in commercial practice.

The carrier 2| is preferably a metal member 20 that is H-shaped in cross section, the member comprising two longitudinal side walls 24 and interconnected by an intermediate wall or web 20.

25 permit the desired pivotal movement vertically of each blade relative to the carrier, each blade is mounted in a longitudinal slot 21 in the carrier web.26. To achieve the required distribution of the blades, with respect to the circumference of a perforated liner in an oil well, the blades are mounted to extend alternately from the opposite faces of the carrier web 26 and the carrier is formed to what may be termed a twisted con'- figuration, the carrier including the web 26 being progressively twisted 180 about its longitudinal axis between the upper and lower ends of the carrier.

To limit the extension or outward movement of each cleaning member or blade 20, stop means 40 30 is provided at the rear end of the blade to abut the corresponding face of the carrier-web 26. In the particular construction shown, the stop means comprises a pin 3| on which is rotatably mounted a pair of sleeves 3,2 on opposite sides of `the blade to function as rollers and thereby favor free vertical movement of the stop means within the range permitted by the longitudinal SIO 2"'.

Preferably each of the slots 2l is of flaring configuration as viewed in longitudinal section. Fig.

2 shows a slot 21 having a relatively short longitudinal dimension A at one face of the carrierweb 2B and a substantiallyr greater longitudinal dimension B at the opposite face, the shorted dimension being on the face against which the stop means 30 abuts and the longer dimension being on the facefrom which the blade extends outward from the carrier. It will be noted that a slot 21 of the indicated configuration permits r0- tationV of the corresponding blade 20 through a relatively extensive vertical arc about the stopmeans 30 as a pivot, but at the same time restricts the vertical movement of the pivot to a range substantially less than the maximum dimension of the slot. I have found that if a blade having a width of approximately 5A," is to be mounted in a carrier-web approximately 1/2 thick, a slot of the required configuration and dimensions for the blade may be cut with a circular cutter 31/2 in diameter, the cutter being caused to penetrate the web from one side of the web suillciently to make a cut approximately 11/4" long on the other side of the web.

A yielding means for urging the leading or extended end of the blade outward from the car- To permit the blades 20 to retract, the blades are slidingly mounted in the carrier 2|, and to rier 2| may comprise a leaf spring II of bowed configuration confined between the face of the carrier-web 20 and some projection on the blade. each end of the bowed leaf spring being bent outward to form a foot 31 in sliding contact with the 5 'face of the carrier-web. In the particular construction shown, each leaf spring 25 is apertured to receive the corresponding blade 20 and presses outward against a cotter pin 2B that is mounted in the blade. To permit a degree of vertical 10 movement of the blade 20 with respect to the leaf spring I5 the aperture in the leaf spring through which the blade extends may be in the form'of an extensive longitudinal slot I8. It will be noted that the range of pivotal movement of l5 the blade permitted by the slot increases if the leaf spring 35 is flattened toward thel face of the carrier-web 26, and it will be noted that since the spring is in sliding relationship to lthe carrier-web, the slotl 38 in the spring in no case 20 imposes a final limit on the vertical movement of the blade in either direction.

In the preferred form of the device shown/.in Fig. 1 the succeslve blades 20 are disposed on opposite faces of the carrier-web 26. Such an 25 arrangement permits the successive blades to be relatively close together since one bowed leaf spring 25 may longitudinally overlap another without interference in function..

It is apparent that after the carrier 2| is low- 30 ered on the cable 22 into a perforated oil well liner, any vertical, movement of the carrier will cause some of the blades 20 to register with liner perforations to achieve some cleaning effect. It is contemplated that in the preferred practice of 35 my invention a spudding action will be employed, the cable beingreciprocated by a crank or other means at the surface of the well. In the preferred procedure the device will be lowered first to the lower end of the perforated liner, spudded 40 through aA suitable range of say 18" for a short operating period, and then raised, say, 12" to 18'.' for another spudding period, the device be ing elevated in this manner by stagesthrough the length of the perforation zone. 45

The variation in the load imposed on the cable 22 when the cable is spudded or reciprocated in the described manner causes the cable to alternately twist and untwist. The lower end of a 5000 foot cable carrying my device may spin 5 as much as fifty revolutions on each of the opposite strokes of the cable. To prevent a torque of undesirable magnitude from being transmitted from the lower end of the cable 22 to the carrier 2|, I may attach the carrier to the cable by 55 a swivel connection. A feature of the preferred form of my invention is the concept of incorporating a diferential effect in such a swivel whereby the alternate twisting and untwisting of the cable rotates the carrier progressively in one dio rection to favor thoroughgoing exploration of the liner interior by the plurality of cleaning blades 20. f

The construction of such a swivel may beunderstood by referring to Fig. 2. The lower end of 65 the swivel, generally designated 40, is connected with the carrier 2| by a knuckle joint that includes a knuckle member 4| and a pin 42. The upper end of the swivel 40 is connected to the cable 22 by a tool joint, the upper end of the 7 swivel being formed as a pin collar 43 to engage a box collar 44 that is mounted on the end of the cable.

The pin collar 43 is hollow and is threaded onto a special bearing bushing I5 at its lower 75 to the carrier.2|.

end. 'A shank 4l of the knuckle member 4| extends axiallythroughthe bushing into the interior of the pin collar 43, and screw-threadedly carries on its inner end a nut or threaded collar 49 to serve as a thrust collar, the nut or collar 49 being secured against rotation by a lock nut 50 carrying a cross pin 5|. To minimize friction and encourage the desired differential effect, a ball-bearing 52 is interposed between the thrust collar 49 and the upper end of the bearing bushing 45. The knuckle member 4| is tapered just below the shank 4'|' to form a conical shoulder 54, and the lower end of the bearing bushing 45 is cut away to form a conicalseat 55 complementary to the shoulder 54.

'I'he maximum load imposed on the cable 22 is at the end of the downward stroke and the beginning of the upward stroke at which time the inertia of the descending carrier is overcome and the upward movement is initiated. The cable untwists for a number of revolutions asthis load rises to maximum. 'Ihe untwisting rotation at the lower end of the cable has relatively little direct effect on the carrier 2|, since any torquetransmitted must pass through the ball-bearing 52. At the end of the upward stroke and the beginning of the downward stroke, the load imposed on the cable drops sharply and the inertia of the upwardly moving carrier tends to carry the conical shoulder 54 into at least momentary engagement with the lconical seat 55. At the time of contact between the shoulder and the seat the drop in the load on the cable permits the cable to twist back toward unstressed disposition, the lower end of the cable turning in the direction of tightened twist, and at such time the relatively high friction caused by the contact between the shoulder 54 and the seat 55 causes appreciable torque to be transmitted from the cable It is apparent thatbecause of this temporary friction the twisting 'action of the cable at the top of the cable reciprocation has a greater rotative effect on the carrier than the untwisting action-of the cable at the bottom 45 of the reciprocation. In consequencethe'carrier tends to be rotated progressively by the successive reciprocations of the cable 22, especially if the reciprocation is at a suiiiciently rapid rateto favor frictional contact between the `conical 5 shoulder 54 and the conical seat 55.

'I'he operation of my invention may be readily understood from the foregoing description'and may be further appreciated by considering Figs. 4 to 10. Fig. 4 taken at the bottom of a downward stroke oi the device shows an upwardly pointing blade 2li just below a perforation 5|I in an oilwell liner 6|. Fig. 5 taken in the early part of the subsequent upward stroke shows the blade 20 extending into the perforation 60, the

blade pressing against the upper end of the perforation in a highly eective manner. The perforation may be either a circular aperture or a longitudinal slot. As indicated in Fig. 6 the engagement oi' the blade with the perforation 60 5 causes the blade to be swung through a horizontal position as the carrier 2| proceeds upward from the position of Fig. 5. With continued upward movement, the blade is swung downward through horizontal to the position indicated by Fig. 7, and it is to be particularly noted that as the blade swings downward between the positions of Fig. 6 and Fig. 7 and continues to swing downward to withdraw from the perforation 60, the blade performs a prying operation, the fulcrum of the prying action being at the upper end of the per- 'foration into the interior of the linerl 5|. The

prying action is positive and there is no possibility of the inwardly displaced material subsequently clogging the perforated liner.

As the reciprocation of the device is continued, the same .blade or some other blade approaches the same perforation 50 in a downward direction as indicated in Fig. y9 to penetrate with cleaning action the lower end of the perforation 60 and then to exert a prying action from the lower end of the perforation.' It is apparent that when the device is properly operated, each perforation will be alternately penetrated from above and below in the manner described. -By periodically shifting the range of reciprocation upwardly, the perforated extent of the liner is'eventually traversed in a thoroughgoing manner.

-'I'he blades 20 will be eective for clearing the perforations whether the blades are pointed or not. The blades should be pointed, however, to facilitate penetration and in the preferred form of my invention I provide rounded points. The rounded configuration of the leading end of the blade permits the blade to ride over minor irregularities in the inner surface of the liner 5| without binding.v

In the preferred form of my invention the length of each of the blades 20 is slightly less than the inside diameter of the perforated liner .permit a blade to be rotated past horizontal when the leading end of the blade is blocked by some formidable obstruction in the liner.- Fig. ll, for example, shows a deposit or projection 62 on` the inner surface of the liner 6| that blocks the path that would normally be taken by the point of a blade 20 as the carrier 2| moves upward. My yielding construction permits the blade to retract and pivot about the obstruction, the blade in pivoting swinging through a horizontal position and thenY pointing downward to ride over the obstruction as the blade continues to be carried upward by the carrier. It is apparent that a blade iloatingly mounted to yield in the various ways described above will not jam in the liner nor in the perforations of the liner. Notwithstanding the yielding construction, positive and eective cleaning action may be obtainedby using leaf springs of proper strength. If it is desirable to increase the strength of the leaf spring action for employment in some particular well, a relasprings may be sub.,

may be employed for the purpose of exporing an oil well to ascertain the depth of a perforated liner in the oil well. The faces of the blades 20 become scratched or otherwise visibly worn only when they penetrate perforations in oil well liners. It does not require any tspecial skill to note the condition 'of the blades prior to lowering of the device in a well and then again to note the condition of the blades after the device is Withdrawn from the well to ascertain whether or not the blades have penetrated perforations. In one practice I coat the blades with paint or some quick drying material prior to the lowering of the device into the well, and after the device is withdrawn only a glance is necessary to asceru cleaningmember.

tain whether or not the coating on the faces of the blades has been scratched. The device is lowered to successively lower levels in the oil well and withdrawn to note the condition of the blades after each of the successive levels is reached. Whenever the process progresses to the y actual level of the perforated liner fresh marks are scratched on the blades and are observed by the operator in the course of the next inspection at the top of the well.

The foregoing description of a preferred form -of my invention given in specific detail for the purpose of illustration and disclosure will suggest to those skilled in the art various changes, modifications, and substitutions that do not depart from my underlying inventive concept, and

I reserve the right to all such changes, modifications. and substitutions that properly come within the scope of my appended claims.

I claim as my invention:

1. A device for cleaning perforations in an oil well liner, including: a carrier adapted for vupand-down movement in the liner; a plurality of cleaning members extending laterally from the carrier, each of said cleaning members being mounted on the carrier for both pivotal movement and bodily shift towards the carrier; and yielding means acting between the carrier and said cleaning members to urge the cleaning members bodily outward from the carrier towards extended positions of the cleaning members thereby to cause the cleaning members to enter perforations in said liner.

2. A device for cleaning perfor-ations in an 'oil .well liner, including: a carrier adapted for upand-down movement in the liner; a plurality of pivot members; yielding means normally extending laterally from the carrier and yieldingly urging said pivot members outward from the carrier;

and a plurality of cleaning membersV retractably extending outward from said carrier, each of said cleaning members being mounted on one of said pivot members to rotate about the axis of the 3. A device for cleaning perforations in an oil well liner, including: a carrier adapted for up-` and-down movement in the liner,fsaid carrier having a plurality of longitudinal slots of flaring configuration in longitudinal section; a plurality of cleaning members slidingly mounted respectively in said slots yand extending laterally from the carrier in the directions in which said slots are flared; a plurality of leaf springs, each of said leaf springs being slidingly mounted on said carrier in engagement wi-th one of said cleaning members to urge the cleaning memberloutward from the,` carrier into liner perforations; and stop means to limit. said outward movement of each cleaning member at an extended position and to provide a pivot for .the extended cleaning member to rotate with a prying action in a liner perforation. y

4. A combination as set forth, in claim 3 in which each of said stop means is movable vertically within a range permitted by the length of the corresponding longitudinal slot in the carrier and in which each of said cleaning members extends through a longitudinal slot in the corresponding leaf spring.

5. A device for cleaning perforations in an oil well liner, including: a carrier adapted for upand-down movement in the liner; a plurality of cleaning members extending laterally from said carrier, each of said cleaning members being slidingly mounted in said carrier; yielding means 6. A device for cleaning Vperforations in an oil well liner, including: a carrier adapted for up-and-down movement in the liner; -a plurality of laterally directed `cleaning members. each cleaning member being mounted on said carrier for both pivotal movement and movement longitudinally of the cleaning member; and yielding means acting between the carrier and said cleaning members to urge the cleaning members laterally outward from the carrier thereby to .cause the cleaning members to enterperforations in said liner, each of said cleaning members being shorter than the internal diameter of said liner to permit the cleaning member to retract and swing through a horizontal position when the carrier moves the outer end of the cleaning member against an obstruction in the liner.

7. A device for cleaning perforations in an oil well liner, including: a carrier having a plurality of longitudinal slots; a plurality of cleaning members,` each of said members being slidingly mounted in one of said slots to move outward and inward relative to the carrier and being adapted for pivotal movement up-and-down in the slot; and yielding means to urge each of said cleaning members outward from the carrier into a liner perforation.

8. A device for cleaning perforations in an oil well liner, including:- a carrier having a plurality of longitudinal slots; a plurality of cleaning members directed laterally from said carrier, each.

of said cleaning members being slidinglyv mounted in one of said slots for outward and inward movement relative to the carrier and for upand-down swinging movement; stop means near' the inner end of each cleaning member to limit the outward movement -of the cleaning member; and yielding means engaging each of said cleaning members at a point spaced outward from said stop, said yielding means being adapted to urge the cleaning member outward to penetratev each of said cleaning members is shaped in pro`` ille at its outer end to ride over minor irregularities in the inner liner surface when the cleaning member is forced along said surface with its outer end foremost. i

11. A device for cleaning perforations in an oil well liner, including: a carrier having a plurality of longitudinal slots, said carrier being of twisted configuration to dispose said slots in various radial directions relative to said liner; a plurality of cleaning members, each of said members being slidingly mounted in one of said slots to move outward and inward relative to .the carrier and being adapted for pivotal movement up-anddown in the slot; and yielding means to urge each of said cleaning members outward from the carrier into a liner perforation.

12. A device as set forth in claim 11 in which said carrier in conguration is twisted through at least approximately 180 and in which cleaning members of said'plurality of cleaning members extend from'opposite faces of the carrier whereby the directions in which the cleaning members extend range through 360.

13. A device for cleaning perforations in an oil Well liner, including: a carrier adapted for up-and-down movement in the liner; a plurality of members mounted on said carrier for movement outward from the carrier into perforations of the liner; means to attach the carrier to a cable for lowering into said liner and subsequent reciprocation in the hner; and a differential bearing between the carrier and said attaching means offering substantially greater resistance to relative rotation in one direction than in the opposite direction thereby to cause the 'alternate twisting of the cable in the course of said reciprocation to cause progressive rotation of the carrier in one rotary direction.

14. In an apparatus for cleaning perforations in an oil well liner including a cable, a carrier connected with the cable and a plurality of members on the carrier for penetrating the liner perforations, the combination therewith of: a thrust bearing for transmittingy force in one direction between said cable and carrier; and a second thrust bearing for transmitting force in the opposite direction between said cable and carrier,

said second thrust bearing being adapted to provide greater resistance than the first thrust bearing to relative rotation between the cable and carrier whereby alternate twist in the cable when the cable is reciprocated will cause the carrier to rotate progressively in one rotary direction.

15. The method of employing a device with perforation-penetrating members to explore an oil well to ascertain the location of a perforated liner therein, said method comprising the steps of: noting the condition of surfaces of said perforation-penetrating members; lowering said device into a wellto a. known depth; withdrawing the device from the well; and noting the condition of the surfaces of said perforation-penetratingmembers to ascertain whether or not said surfaces have been scratched by the penetration of perforations by said members.

16. The method of employing a device with perforation-penetrating members to explore an oil well to ascertain the location of a perforated liner therein, said method including the steps of: coating surfaces of said members that make contact with the material of a liner when the members penetrate perforations of the liner; lowering said device into the well to a known depth; and withdrawing the device from the well to note the condition of said coating.

SAMUEL V. SMITH. 

